Greetings ladies and gentlemen,
I believe that the last version of OSX to have OpenMPI shipped with the dev tools or the OS was Snow Leopard. That version I believe was version OMPI 1.29.

I am starting to get back to working with MPI myself. The last time I worked with MPI, I basically wrapped the C function into Objective-C. Often I would let Objective-C do the marshaling for me, and have MPI do the message passing itself.

I have read that OMPI from source works on Mountain Lion, but there are some dependencies to make it work with LLVM and to make GCC-Fortran transition to LLVM.

If there are some gurus out there who have done this fill us with wisdom.

> I've discovered MPI recently, and I would like to start to write some applications to use it's potential.
>
> Now the problem is that I use a mac, and I see no tutorials or books that are targeting OSX, so I was wondering if you could give me some pointers about where to find info.
>
> I use Xcode; from what I can understand, MPI uses C, so I need to use a console application template for Xcode. I do not see any wrapper for Objective-C, so I assume that C is the only language used for MPI?

There is also C++ and Fortran support, while the C++ interface is deprecated as the C one will do here too.

> Thanks in advance for any info that you can give me; I really like the idea to use MPI for scientific applications, but I am totally new to this (I have experience in C++ on Windows, and a bit of Objective-C on mac). I would love to see tutorials that explains how to do simple apps on mac using MPI, but if they exist, they are very well hidden :)

With some versions of OS X it's installed already - well an older version. Can you issue:

$ ompi_info

on the command line? As MPI is a standard which is not targeting any specific platform, most of the tutorials should apply here too, as long as they don't access any OS specific functions.